Lead weight-making apparatus

ABSTRACT

Lead weights for the balancing of automobile wheels are formed in an automatic operation. Molten lead is fed from a bath thereof to a lead weight-forming mold cavity defined by plates in edge abutting relationship and a block located in face abutting relationship with the plates and having a depression formed in the face thereof abutting the plates. The abutting edges of the plates have a groove formed therein extending the depth of the plates and defining a lead conveying passage. A weight retaining clip feed means is provided to feed individual clips from a source thereof to a holding station and clip positioning means is provided for moving individual clips from the holding station to the molding station. The plates include clip support means to support the clips at the molding station. A cutting knife is provided for removing tails from the weights after formation thereof.

' United States Patent [191 Boberg LEAD WEIGHT-MAKING APPARATUS Jarl A. Boberg, Scarborough, Canada [73] Assignee: A. B. Machine Company,

Scarborough, Canada 22 Filed: Jan. 9, 1974 21 Appl. No.: 431,893

[75 Inventor:

[56] References Cited UNITED STATES PATENTS 6/1964 Sunday 164/332 X 10/1964 Hart 164/333 Primary ExaminerFrancis S. Husar Assistant Examiner-Carl Rowold Attorney, Agent, or FirmSim & McBurney Nov. 4, 1975 [57] ABSTRACT Lead weights for the balancing of automobile wheels are formed in an automatic operation. Molten lead is fed from a bath thereof to a lead weight-forming mold cavity defined by plates in edge abutting relationship and a block located in face abutting relationship with the plates and having a depression formed in the face thereof abutting the plates. The abutting edges of the plates have a groove formed therein extending the depth of the plates and defining a lead conveying passage. A weight retaining clip feed means is provided to feed individual clips from a source thereof to a holding station and clip positioning means is provided for moving individual clips from the holding station to the molding station. The plates include clip support means to support the clips at the molding station. A cutting knife is provided for removing tails from the weights after formation thereof.

14 Claims, 13 Drawing Figures U.S. Patent Nov. 4, 1975 Sheet 1 of6 3,916,986

US. Patent Nov. 4, 1975 Sheet2 of6 3,916,986

US. Patent Nov. 4, 1975 Sheet 3 of6 3,916,986

US. Patent Nov. 4, 1975 Sheet4of6 3,916,986

FIG. 1O

US. Patent Nov. 4, 1975 Sheet 5 U.S. Patent Nov. 4, 1975 Sheet 6 01-6 3,916,986

[Ill r FIG. 13 t?- LEAD WEIGHT-MAKING APPARATUS I FIELD OF INVENTION This invention relates to the production of lead weights, in particular to apparatus for use in producing lead weights for automobile use.

BACKGROUND OF THE INVENTION Lead weights are commonly used in balancing automobile wheels, and generally include an arcuately shaped elongated body made of lead, the degree of curvature corresponding to the curvature of the wheel rim, and a clip secured to the body for attaching the weight to the wheel rim.

Lead weights have commonly been made on machines having molds into which molten lead is injected and in which the clip is positioned. Manual procedures are utilized for operation of these apparatus including manual positioning of the clips in the mold and manual closing of the mold. Such procedures are time consuming, and dangerous to the operator due to the proximity of the bath of molten lead to the mold cavity in which the clips are positioned, and residual heat in the weight immediately after formation thereof. The rate of production of these manually operated machines is determined by the speed of the operator, leading to wide variations which may affect production schedules. Further, existing lead weight-making machines suffer from the drawback that the weights have a tail, corresponding to the cooled lead present after cooling, in the molten lead feed line leading to the mold. The tails must be removed after cooling in a separate, time consuming, procedure to provide a useable lead weight.

SUMMARY OF INVENTION In accordance with the present invention, there is provided a lead weight-making machine which is able to produce lead weights automatically without the use of manual procedures, and hence is not subject to the vagaries of manual operation, and which eliminates the need to remove tails in a separate step.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is an overall perspective view of a lead weightmaking machine in accordance with one embodiment of the invention;

FIG. 2 is a close-up perspective view of a portion of the apparatus of FIG. 1;

FIG. 3 is a sectional view of the apparatus of FIG. 1 taken along line 3-3 thereof;

FIG. 4 is a side elevational view of the jaws of the clip-positioning portion of the apparatus of FIG. 1 in a first position;

FIG. 5 is a side elevational view of the jaws of the clip-positioning portion of the apparatus of FIG. 1 in a second position;

FIG. 6 is an elevational view of the feed clip holder of the apparatus of FIG. 1, when the jaws of the clip positioning portion are as shown in FIG. 4;

FIG. 7 is an elevational view of the feed clip holder of the apparatus of FIG. 1, when the jaws of the clip positioning portion are moving towards the position shown FIG. 9 is an elevational view of the backing plate jaws of the mold in a second position with the corresponding position of the pin in the slot being indicated;

FIG. 10 is an elevational view of the backing plate jaws of the mold in a third position with the corresponding position of the pin in the slot being indicated;

FIG. 11 is an elevational view of a weight produced by the apparatus of FIG. 1:

FIG. 12 is a part sectional view of the apparatus of FIG. 1 when the tail is cut from the weight;

FIG. 13 is a part sectional end view taken in a direction of arrow 13 in FIG. 1.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring to the drawings, a lead weight-making apparatus 10 includes a molten bath of lead 12 which is maintained molten in any convienient manner and weight-making molding equipment 14.

A cylindrical bowl 16 contains a mass of individual clips 18 which are formed into a continuous stream 20 thereof on a downwardly inclined support 22, the downwardly inclined support 22 terminating in a substantially horizontal support 24. A predetermined number of clips 18 is maintained in the stream 20 by use of a suitable sensor (not shown) which actuates the bowl 16 from time to time as required.

The stream 20 of individual clips 18 terminates at a feed station 26 consisting of a support arm 28 which is pivoted at 30 and forming part of the horizontal support 24, the arm 28 normally being biased to the horizontal position shown in FIG. 6 by the action of spring 32 and stop means 34.

A clip positioner 36 includes reciprocably movable jaws 38 which are connected to a piston rod 40 actuated by pneumatic cylinder 42 or any other convenient actuation device. The jaws 38 consist of a first jaw 44 which has a concave inner surface 46 at its lower extremity and a second jaw 48 having a concave inner surface 50 at its lower extremity and opposite the concave inner surface 46. The concave surfaces 46 and 50 cooperate to define a recess normally of substantially the shape and dimension of the clips 18 whereby a clip 18 may be gripped between the jaws 44 and 48.

The second jaw 48 is mounted by pivot pin 52 on the first jaw 44 and the second jaw 48 is biased by a compression spring 54 situated between arms 56 and 58 of the jaws 44 and 48 respectively The compression spring 54 biases the concave surfaces 46 and 50 of the jaws 44 and 48 towards each other to establish a releasable grip on the clip 18.

A cam follower element 60, in the form of a rod, is secured to the jaw 48 and extends through an opening 62 in the jaw 44 to sit normally in a groove 64 situated in a plate 66 which constitutes with the raisedportions at each vertical extremity of the groove 64, a cam for engagement by; the cam 60. The plate 66 forms part of the clip positioner 36 and is stationary with respect to the jaws 38. When the rod 60 is located in the groove 64 during vertical movementof the jaws38, they are in their normal, clip gripping position, which ma y 'be described as closed. I-Iowever,',as-may seen'more clearly in FIGS. 4 and 5, in both the lower andupper extremities of the reciprocal travel'ofthefjaws 38, the rod 60 rides up out of the groove 64,c'aiis ingpivotal movement of the jaw 48 relative to jaw 44 against the action of spring 54 thereby moving the concave sur- 3 tion may be referred to as open.

A pump 68 is positioned in the molten bath 12 to pump molten lead from the bath 12 to a mold cavity wherein the weight is formed. The pump 68 may be of any convenient form, actuated by a pneumatic cylinder 70, or any other convenient actuation device, and includes a cavity 72, a one-way valve 74 and a reciprocable plunger 76. As the plunger 76 rises, molten lead is drawn from the molten bath 12 into the cavity 72 through the one-way valve 74. The molten lead may be ejected from the cavity 72 upon downward movement of the plunger 76, although such ejection cannot occur through the one-way valve 74 since it now is closed. A passageway 78 communicates with the cavity 72 for converging molten lead away from the cavity 72 upon downward movement of the plunger 76. The passageway 78 terminates in an orifice 80.

The passageway 78 may be surrounded by a suitable heating device 82 to maintain the lead in the passageway 78.

The mold cavity to which the molten lead is fed through the passageway 78 is provided by a number of elements. A pair of mold backing plates 84 and 85 is movable towards and away from each other, assuming several positions during such movement, as illustrated generally in FIGS. 8 to and discussed in more detail below.

The backing plates 84 and 85 each is provided with a groove 86 in the facing edges surfaces thereof, which together define a conduit 88 extending through the plate 84 from the orifice 80 when the plates 84 and 85 are in edge-abutting relationship as seen in FIG. 10.

The backing plates 84 and 85 each has a shoulder 90, 91 diverging in width from the abutting edge and difining with the remainder of the plate on inclined surface 92 and 93. The shoulders 90 and 91 adjacent the inner edge of each plate is shaped to support a clip 18 between positions where the plates 84 and 85 are slightly spaced apart from each other and where the plates 84 and 85 abut each other. The shoulders 90 and 91 cooperate to provide a support for a clip 18 in the manner seen in FIGS. 9 and 10.

A mold cavity plate support member 94 is mounted for reciprocal movement on support rods 96 secured to a fixed frame98, only part of which is shown in FIG. 1. Reciprocal movement of member 94 is actuated by a pneumatically, or otherwise controlled cylinder 100 through piston rod 102 and articulated links 104.

A depression 106 is provided in an elongated block 108 mounted on the member 94 with its open side facing the backing plates 84 to define with the inclined surfaces 92 and 93 a mold cavity 110 which is in fluid flow communication with the bath 12 through passageway 78 and conduit 88.

The depression 106 may be provided directly in member 94, if desired, although it is preferred to form it in the elongated block 108, since, the block 108 may be readily replaced to provide a mold cavity 110 of any desired length, depending on the length of the depression 106 in the individual block 108. The depression 106 isarcuatelyjshaped, complementary to the arcuate shape of the inclined'surfaces 92 and 93, to provide an arcuate moldcavity 1 10 of radius of curvature substantially that of the wheel rim to which the weight is to be pp e I A sensor 112 extends through the member 94 to sense the presence of a'clip 18 when the mold cavity 110 isbeing filled. The importance of this feature will 4 become apparent hereinafter when the operation of the apparatus is discussed.

A cam follower element in the form of a pin is provided upstanding from and attached to a flat plate-like member 132 formed integral with each plate 84, 85 at the outer extremity thereof. As seen in the end view of FIG. 13, each pin 114 is positioned in and engages a cam track element in the form of a slot 116 formed in the underside of plate-like members 134, 136 attached to the member 94 to provide a mechanical interconnection between the member 94 and the plates 84, 85.

Upon movement of the member 94 forwardly and rearwardly, the slot 116 moves relative tothe pin 114 with the pin engaging the walls of the slot, and thereby causing positioning of the plates 84 and 85 with respect to each other and causing the same to assume the open, intermediate and closed positions of FIGS. 8, 9 and 10 respectively with the appropriate relative location of the slot 116 and the pin 114 being shown therein.

A knife element 118 is reciprocable by a pneumatically operated cylinder 120 between a normal retracted position, as illustrated in FIG. 3, and an extended position, as illustrated in FIG. 12, wherein the element 118 extends through a slot 122 and beyond the opening of the conduit 88 between the plates 84 and 85.

An ejection chute 124 is positioned below the elements defining the mold cavity 110 to receive finished weights from the apparatus 10 and guide them to a collecting bin or the like.

The apparatus 10 described above with reference to the drawings is capable of forming lead weights 126 of the type shown in FIG. 11, having an elongated curved body 128 in which is embedded a clip 18.

OPERATION The cycle through which the apparatus 10 goes to produce the lead weights is controlled by actuation of the appropriate pneumatic cylinders in properly timed sequence. The timing and actuation may be provided electronically or in any other convenient manner. In this way, the necessity for manual operation is avoided.

At the commencement of the cycle, a clip 18 is supported by the arm 28 in the position shown in FIG. 6, the member 94 is in its fully retracted position as in FIG. 2 with the pin 114 being positioned in the slot 116 in the position shown in FIG. 8, and the jaws 38 of the clip positioner 36 grip the clip 18 as seen in FIG. 3. During a previous cycle, the jaws 38 moved to their fully retracted position and were open, as seen in FIG. 4. The jaws 38 then moved downwardly to engage and grip the clip 18.

The member 94 slides towards the plates 84 and 85 along the rods 96. During these acts the plates 84 and v 85 move towards each other, moving between the posi groove 64 and the jaws are opened to release the clip 18, as shown in FIG. 5 to allow the clip 18 to engage the shoulders 90 and 91. During this movement, the plates 84 and remain in the same relative position as the pin 114 moves in the straight portion of the slot 116 and the arm 28 is pushed out of the line of movement of the jaws 38 as seen in FIG. 7.

Thereafter, the mold 110 is formed by movement of the plates 84 and 85 to their edge abutting position as seen in FIG. 10, retraction of the jaws 38leaving the clip 18 positioned on the shoulders 90 and 91 of. the plates 84 and 85, and movement of the member 94 so that the block 108 contacts the edge abutting plates 84 and 85 while the pin 114 assumes the position shown in FIG. 10. In the mold-closed position, shown in FIG. 3, the sensor 112 senses the presence or absence of a clip 18.

If a clip 18 is present, as it will be in normal operation, appropriate actuation of the pump 68 causes molten lead to flow through the passageway 78 and the conduit 88 and into the mold cavity 1 10. The mold usually is water cooled so that the molten lead present in the cavity 110 and the conduit 88 is solidified.

In the absence of a clip 18, such as, where no clips are fed to the arm 28, the pump 68 is not actuated and the parts return to their initial position. Upon resumption of the feed of clips 18, the weight-making proce dure recommences. The sensor 112, therefore, is important to ensure that the machine does not continue to make lead weights when the supply of clips is exhausted or otherwise defective.

The retraction of the jaws 38 proceeds to the position shown in FIG. 4 i.e., with the jaws 38 open, and allows the arm 28 to resume its original position, so that the next clip 18 of the stream 20 is positioned on the arm 28. When the clip 18 is so positioned, the jaws 38 then move into gripping engagement therewith, as seen in FIG. 3.

After solidifying the lead, the member 98 retracts, along with the plates 84 and 85 which retract to the position shown in FIG. 9. It will be observed at this point that the weight is in the form shown in FIG. 11 with an additional tail 130, shown in phantom outline. It is in this form that prior art manually actuated machines produce lead weights, such weights requiring a further step to remove the tail.

The knife 118 is actuated and cuts the tail 130 from the weight 126, as may be seen in FIG. 12. Upon further retraction of the plates 84 and 85, along with the member 94, the weight 126 is released from the shoulders 90 onto the chute 124 and have discharged from the apparatus. The apparatus then has resumed its starting position and the cycle is repeated.

SUMMARY It will be seen, therefore, that the apparatus of the present invention is able to produce lead weights which may be used directly without the prior art necessity of a separate operation to remove the tails. Further, the

apparatus may operate substantially continuously without supervision or manual operation, other than to ensure an adequate supply of clips and molten lead.

Modifications are possible with the scope of the present invention.

I claim: 1. An apparatus for forming lead weights for the balancing of automobile wheels which comprises:

container means for holding a bath of molten lead, a lead weight-forming mold cavity situated at a molding station, liquid lead feed means for conveying molten lead from said bath to said mold cavity, said mold cavity being defined by first and second plates situated in edge-abutting relationship and a block located in face-abutting relationship with said first and second plates, said block having a depression formed in the face thereof abutting said first and second plates,

said first and second plates being mounted for relative movement between a first stationary position in which the plates have said edge-abutting relationship and a second stationary position in which the plates are remote from said edge abutting relationship through an intermediate stationary position between said first and second stationary positions,

said block being mounted on a carrier member for reciprocal movement in a substantially horizontal plane between a first position wherein said block is located in said face-abutting relationship with said first and second plates and a second position horizontally remote from said first position,

the abutting edges of each of said first and second plates having a groove formed therein extending the depth of the plates, the grooves cooperating to define a lead conveying passage constituting part of said liquid lead feed means when said first and second plates are in said edge-abutting relationship,

weight retaining'clip feed means to feed individual clips from a source thereof to a holding station, clip positioning means for moving individual clips from said holding station to said molding station,

clip supporting means on said first and second plates for supporting a clip at said molding station with part thereof extending into said mold cavity,

mechanical interconnecting means operably connecting said carrier member and said first and second plates for phased movement of said carrier member and said first and second plates between said first and second positions thereof for locating said carrier member at its first position when said first and second plates are located in their first position and at its second position when said first and second plates are located in their second position,

said, mechanical interconnecting means comprising first and second elongate cam track elements associated with one of said carrier member and said first and second plates, first and second cam follower elements mounted respectively on the other of said carrier. member and said first and second plates and each extending into engagement with one of said cam track elements for control of the position of said first and second plates relative to each other according to the positioning of said cam follower elements along the length of said cam track elements,

each of said cam track elements having first and second track portions in which the respective cam follower element moves to cause displacement of said first and second plates relative to each other during predetermined phases of movement of said carrier member between ,said first and second positions and an intermediate track portion between said first and second track portions to cause holding of said first and second plates at said intermediate stationary position thereof during the phase of movement of said carrier member intermediate said predetermined phases of movement thereof,

said mechanical interconnection being arranged to position said first and second plates to support a clip at said molding station at both said first and intermediate positionsthereof but not at said second position thereof and 7 knife means movable between a first inactive position and a second position wherein said knife means extends over the orifice to said lead conveying passage, whereby any solidified lead in said passageway may be detached from a lead weight formed in said mold cavity.

2. The apparatus of claim 1 wherein said liquid lead feed means comprises pump means and conduit means extending from the outlet of said pump means to said mold cavity.

3. The apparatus of claim 1 wherein said first and second plates each include a shoulder raised from the surface of the plate and increasing in width from the abutting edge to the opposite edge, said shoulder defining an incline with the surface of the plate which is curved across the face of the plate, and the depression in the block is cruved across the abutting surface, the inclines of said plates coinciding with the depression in the block to provide a curved mold cavity.

4. The apparatus of claim 3 wherein said shoulders are shaped adjacent said abutting edge to provide said clip supporting means.

5. The apparatus of claim 1 wherein said holding station comprises an arm biased to a normally horizontal position, adapted to receive and support a clip and pivoted for downward movement against said biasing under the application of a downwardly-directed biasovercoming force to said arm.

6. The apparatus of claim 5 wherein said clip positioning means comprises substantially vertically-reciprocable jaw means, said jaw means in a normally closed position being capable of gripping a clip, said jaw means at the upper and lower vertical extremities of its travel being open and incapable of gripping said clip.

7. The apparatus of claim 6 wherein said jaw means in its vertical extremity is positioned above a clip positioned on said arm, is movable from said upper vertical extremity to engage said clip and close and grip said clip, is movable downwardly against the biasing of said arm to pivot said arm out of the path of said jaw means while gripping said clip, and is movable to its vertically lower extremity where said jaw means open and said clip is released into said molding station.

8. An apparatus for forming lead weights for the balancing of automobile wheels, which comprises con tainer means for holding a bath of molten lead; a lead weight-forming mold cavity situated at a molding station; liquid lead feed means for conveying molten lead from said bath to said mold cavity; said mold cavity being defined by first and second plates situated in edge-abutting relationship and a block situated in faceabutting relationship with said first and second plates, said block having a depression formed in the face thereof abutting said first and second plates; the abutting edges of each of said first and second plates having a groove formed therein extending the depth of the plates, the grooves cooperating to define a lead-conveying passage consituting part of said liquid lead feed means when said first and second plates are in said edge-abutting relationship; said first and second plates being movable in the plane thereof out of and into said edge-abutting relationship in response to movement of said block out of and into said engagement with said plates; weight-retaining clip feed means to feed individual clips from a source thereof to a holding station located above said molding station; said holding station comprising an arm biased to a normally horizontal position adapted to receive and support a clip and pivoted at one end thereof for downward movement against said biasing under the application of a downwardlydirected bias-overcoming force to said arm; clip positioning means for moving individual clips from said holding station to said molding station; clip supporting means on said first and second backing plates for supporting a clip at said molding station with part thereof extending into said mold cavity, when first and second plates are in said edge-engaging position or spaced apart from each other up to a predetermined distance from each other; and knife means movable between a first inactive position and a second position wherein said knife means extends over the orifice to said lead conveying passage, whereby any solidified lead in said passage may be detached from a lead weight formed in said mold cavity; said clip positioning means comprising jaw means substantially vertically reciprocable between an upper extremity positioned above said arm and a lower extremity at said molding station, during movement from said upper extremity to said lower extremity, said jaw means biasing said arm to pivot said arm out of the path of said jaw means; and jaw means including first and second jaw elements pivotally connected to each other solely for pivotal movement of one of said jaw elements relative to the other and normally biased to a closed position for gripping a clip therebetween, said clip positioning means further comprising a stationary cam element including a substantially vertically-extending channel portion and raised portions at each vertical extremity of said channel portion, said jaw means including a cam follower element engaging said cam element with said cam follower element being positioned in said channel portion when said jaws are in said closed position and said cam follower element being positioned in engagement with one of said raised portions when said jaw means is opened by said pivotal movement of one of said jaw elements relative to the other jaw element against said biasing to a non-clip-gripping position; said cam element, said cam follower element and said jaw means being arranged so that said jaw means is openable at its upper extremity and in its movement downwardly to said holding station; said jaw means is closable at said holding station to grip a clip positioned thereat and in its movement downwardly to said molding station and said jaw means is openable at its vertically lower extremity to release said grip on said clip and position the same at said molding station.

9. The apparatus of claim 1 wherein said knife means comprises a reciprocable knife blade movable in the plane of said plate.

10. The apparatus of claim 8 wherein said block is mounted for reciprocal movement in a substantially horizontal plane between a first position wherein said block is located in said face-abutting relationship with said first and second plates and a second position horizontally remote from said first position.

11. The apparatus of claim 8 wherein said first and second plates each include a shoulder raised from the surface of the plate and increasing in width from the abutting edge to the opposite edge, said shoulder defining an incline with the surface of the plate which is curved across the face of the plate, and the depression in the block is curved across the abutting surface, the inclines of said plates coinciding with the depression in the block to provide a curved mold cavity.

12. The apparatus of claim 11 wherein said shoulders are shaped adjacent said abutting edge to provide said 10 tremity of said channel portions, said jaw means includes a cam follower element with said cam follower element being positioned in said channel portion when said jaws are in said closed position and said cam follower element being positioned in engagement with one of said raised portions when said jaw means is opened by said pivotal movement of one of said jaw elements relative to the other jaw element against said 0 biasing. 

1. An apparatus for forming lead weights for the balancing of automobile wheels which comprises: container means for holding a bath of molten lead, a lead weight-forming mold cavity situated at a molding station, liquid lead feed means for conveying molten lead from said bath to said mold cavity, said mold cavity being defined by first and second plates situated in edge-abutting relationship and a block located in face-abutting relationship with said first and second plates, said block having a depression formed in the face thereof abutting said first and second plates, said first and second plates being mounted for relative movement between a first stationary position in which the plates have said edge-abutting relationship and a second stationary position in which the plates are remote from said edge abutting relationship through an intermediate stationary position between said first and second stationary positions, said block being mounted on a carrier member for reciprocal movement in a substantially horizontal plane between a first position wherein said block is located in said face-abutting relationship with said first and second plates and a second position horizontally remote from said first position, the abutting edges of each of said first and second plates having a groove formed therein extending the depth of the plates, the grooves cooperating to define a lead conveying passage constituting part of said liquid lead feed means when said first and second plates are in said edge-abutting relationship, weight retaining clip feed means to feed individual clips from a source thereof to a holding station, clip positioning means for moving individual clips from said holding station to said molding station, clip supporting means on said first and second plates for supporting a clip at said molding station with part thereof extending into said mold cavity, mechanical interconnecting means operably connecting said carrier member and said first and second plates for phased movement of said carrier member and said first and second plates between said first and second positions thereof for locating said carrier member at its first position when said first and second plates are located in their first position and at its second position when said first and second plates are located in their second position, said mechanical interconnecting means comprising first and second elongate cam track elements associated with one of said carrier member and said first and second plates, first anD second cam follower elements mounted respectively on the other of said carrier member and said first and second plates and each extending into engagement with one of said cam track elements for control of the position of said first and second plates relative to each other according to the positioning of said cam follower elements along the length of said cam track elements, each of said cam track elements having first and second track portions in which the respective cam follower element moves to cause displacement of said first and second plates relative to each other during predetermined phases of movement of said carrier member between said first and second positions and an intermediate track portion between said first and second track portions to cause holding of said first and second plates at said intermediate stationary position thereof during the phase of movement of said carrier member intermediate said predetermined phases of movement thereof, said mechanical interconnection being arranged to position said first and second plates to support a clip at said molding station at both said first and intermediate positions thereof but not at said second position thereof, and knife means movable between a first inactive position and a second position wherein said knife means extends over the orifice to said lead conveying passage, whereby any solidified lead in said passageway may be detached from a lead weight formed in said mold cavity.
 2. The apparatus of claim 1 wherein said liquid lead feed means comprises pump means and conduit means extending from the outlet of said pump means to said mold cavity.
 3. The apparatus of claim 1 wherein said first and second plates each include a shoulder raised from the surface of the plate and increasing in width from the abutting edge to the opposite edge, said shoulder defining an incline with the surface of the plate which is curved across the face of the plate, and the depression in the block is cruved across the abutting surface, the inclines of said plates coinciding with the depression in the block to provide a curved mold cavity.
 4. The apparatus of claim 3 wherein said shoulders are shaped adjacent said abutting edge to provide said clip supporting means.
 5. The apparatus of claim 1 wherein said holding station comprises an arm biased to a normally horizontal position, adapted to receive and support a clip and pivoted for downward movement against said biasing under the application of a downwardly-directed bias-overcoming force to said arm.
 6. The apparatus of claim 5 wherein said clip positioning means comprises substantially vertically-reciprocable jaw means, said jaw means in a normally closed position being capable of gripping a clip, said jaw means at the upper and lower vertical extremities of its travel being open and incapable of gripping said clip.
 7. The apparatus of claim 6 wherein said jaw means in its vertical extremity is positioned above a clip positioned on said arm, is movable from said upper vertical extremity to engage said clip and close and grip said clip, is movable downwardly against the biasing of said arm to pivot said arm out of the path of said jaw means while gripping said clip, and is movable to its vertically lower extremity where said jaw means open and said clip is released into said molding station.
 8. An apparatus for forming lead weights for the balancing of automobile wheels, which comprises container means for holding a bath of molten lead; a lead weight-forming mold cavity situated at a molding station; liquid lead feed means for conveying molten lead from said bath to said mold cavity; said mold cavity being defined by first and second plates situated in edge-abutting relationship and a block situated in face-abutting relationship with said first and second plates, said block having a depression formed in the face thereof abutting said first and second plates; the abutting edges of each of said first and second plates having a groove formed tHerein extending the depth of the plates, the grooves cooperating to define a lead-conveying passage consituting part of said liquid lead feed means when said first and second plates are in said edge-abutting relationship; said first and second plates being movable in the plane thereof out of and into said edge-abutting relationship in response to movement of said block out of and into said engagement with said plates; weight-retaining clip feed means to feed individual clips from a source thereof to a holding station located above said molding station; said holding station comprising an arm biased to a normally horizontal position adapted to receive and support a clip and pivoted at one end thereof for downward movement against said biasing under the application of a downwardly-directed bias-overcoming force to said arm; clip positioning means for moving individual clips from said holding station to said molding station; clip supporting means on said first and second backing plates for supporting a clip at said molding station with part thereof extending into said mold cavity, when first and second plates are in said edge-engaging position or spaced apart from each other up to a predetermined distance from each other; and knife means movable between a first inactive position and a second position wherein said knife means extends over the orifice to said lead conveying passage, whereby any solidified lead in said passage may be detached from a lead weight formed in said mold cavity; said clip positioning means comprising jaw means substantially vertically reciprocable between an upper extremity positioned above said arm and a lower extremity at said molding station, during movement from said upper extremity to said lower extremity, said jaw means biasing said arm to pivot said arm out of the path of said jaw means; and jaw means including first and second jaw elements pivotally connected to each other solely for pivotal movement of one of said jaw elements relative to the other and normally biased to a closed position for gripping a clip therebetween, said clip positioning means further comprising a stationary cam element including a substantially vertically-extending channel portion and raised portions at each vertical extremity of said channel portion, said jaw means including a cam follower element engaging said cam element with said cam follower element being positioned in said channel portion when said jaws are in said closed position and said cam follower element being positioned in engagement with one of said raised portions when said jaw means is opened by said pivotal movement of one of said jaw elements relative to the other jaw element against said biasing to a non-clip-gripping position; said cam element, said cam follower element and said jaw means being arranged so that said jaw means is openable at its upper extremity and in its movement downwardly to said holding station; said jaw means is closable at said holding station to grip a clip positioned thereat and in its movement downwardly to said molding station and said jaw means is openable at its vertically lower extremity to release said grip on said clip and position the same at said molding station.
 9. The apparatus of claim 1 wherein said knife means comprises a reciprocable knife blade movable in the plane of said plate.
 10. The apparatus of claim 8 wherein said block is mounted for reciprocal movement in a substantially horizontal plane between a first position wherein said block is located in said face-abutting relationship with said first and second plates and a second position horizontally remote from said first position.
 11. The apparatus of claim 8 wherein said first and second plates each include a shoulder raised from the surface of the plate and increasing in width from the abutting edge to the opposite edge, said shoulder defining an incline with the surface of the plate which is curved across the face of the plate, and the depression in the block is curved across the abutting surface, the inclines of said plates coinciding with the depression in the block to provide a curved mold cavity.
 12. The apparatus of claim 11 wherein said shoulders are shaped adjacent said abutting edge to provide said clip supporting means.
 13. The apparatus of claim 8 wherein said knife means comprises a reciprocable knife blade movable in the plane of said plate.
 14. The apparatus of claim 7 wherein said jaw means includes first and second jaw elements pivotally connected to each other solely for pivotal movement of one of said jaw elements relative to the other and normally biased to a closed position, said clip positioning means includes a stationary cam element including a channel portion and raised portions at each vertical extremity of said channel portions, said jaw means includes a cam follower element with said cam follower element being positioned in said channel portion when said jaws are in said closed position and said cam follower element being positioned in engagement with one of said raised portions when said jaw means is opened by said pivotal movement of one of said jaw elements relative to the other jaw element against said biasing. 